1. Field of the Invention
The present invention relates to a new fluorene compounds containing various functional groups and polymers thereof which can be used as organic polymer semiconductor and photo-electronic materials, and especially as a material for electro-luminescence (hereinafter, referred to as “EL”), and to an EL element using the same.
2. Description of the Background Art
Generally, polymers of a polyphenylene vinylene (hereinafter, referred to as “PPV”), of a polythiophene (hereinafter, referred to as “PTh”) and of a polyphenylene (refer to Synth. Met., 50 (1-3), P491 (1992) and Adv Mater., 4, p 36 (1992)) are known as organic polymer semiconductor and photoelectronic materials (refer to Semiconducting Polymers: Chemistry, Physics and Engineering, Edited by G. Hadziioannou and P. F. van Hutten) WILEY-VCH (2000)) or as a material for polymer EL (refer to Angew. Chem. Int. Ed., 37, p. 402 (1998), Prog. Polym. Sci., 25, p. 1089 (2000) and Adv. Mater., 12, p. 1737 (2000)). At present, studies for these polymer materials have been made, however, these materials have disadvantages in that the final product is not dissolved in an organic solvent. Also, PPV or PTh derivatives which are improved its processability by introducing an appropriate substituent and illuminate lights of blue, green and red colors are known as the materials (refer to Synth. Met., 62, p. 35 (1994), Adv. Mater., 4, p. 36 (1992), and Macromolecules, 28, p. 7525 (1995)). However, the fabrication processes for these derivatives are very complex, and they have a problem in stability.
Polymers having an acetylene group are also disclosed (refer to Macromol. Chem., 191, p. 857 (1990), Macromolecules, 27, p. 562 (1994), J. Chem. Soc., Chem. Commun., p. 1433 (1995), and Macromolecules. 29. P5157 (1996)), and applications for nonlinear optics or for light conductivity, and photoluminescence (hereinafter referred to as “PL”) are reported (refer to Science, 279, p. 835 (1998)). Also, polymers having a diacetylene group are disclosed (refer to Prog. Polym. Sci., 20, p. 943 (1995), CHEMTECH, October, p 32, (1993)), and Macromolecules, 29, p. 2885 (1996)). These polymers are more sensitive to heat or light than the polymers of acetylene group and therefore a cross-link reaction can be easily taken place. These polymers can be applied for a material of nonlinear optics, a heat resistant polymer, a polarized PL polymer, and an electric or optically active polymer. Applying the polymers having a novel acetylene or diacetylene group to a material for the EL has patented by the present inventors (U.S. Pat. No. 5,876,864 and Japanese Patent No. 3,046,814).
A fluorene-based polymer emitting blue light has also been reported (refer to Jpn. J. Appl. Phys., 30, p. L1941 (1991)). However, it uses a preparation method that can not be applied to a preparation of a polymer having various conjugated double bonds. The present inventors has solved the above problem and disclosed fluorene-based alternating copolymers for EL element having conjugated double bond (U.S. Pat. No. 5,801,974. However, there are few examples of preparing or applying fluorene-based polymers having various functional groups as polymeric EL materials.